package top.mable.utils;

import cn.hutool.core.codec.Base64;
import cn.hutool.core.lang.UUID;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.logging.Level;
import java.util.logging.Logger;


/**
 * @author taffywen
 * @date 2022/3/9 21:10
 */
public class AESUtil{

    private static final String KEY_ALGORITHM = "AES";
    //默认的加密算法
    private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";

    /**
     * AES 加密操作
     *
     * @param content 待加密内容
     * @param key 加密密钥
     * @return 返回Base64转码后的加密数据
     */
    public static String encrypt(String content, String key) {
        try {
            // 创建密码器
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

            byte[] byteContent = content.getBytes("utf-8");

            // 初始化为加密模式的密码器
            cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));

            // 加密
            byte[] result = cipher.doFinal(byteContent);

            //通过Base64转码返回
            return Base64.encode(result);

        } catch (Exception ex) {
            Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
        }

        return null;
    }

    /**
     * AES 解密操作
     *
     * @param content
     * @param key
     * @return
     */
    public static String decrypt(String content, String key) {

        try {
            //实例化
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

            //使用密钥初始化，设置为解密模式
            cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));

            //执行操作
            byte[] result = cipher.doFinal(Base64.decode(content));


            return new String(result, "utf-8");
        } catch (Exception ex) {
            Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
        }

        return null;
    }

    /**
     * 生成加密秘钥
     *
     * @return
     */
    private static SecretKeySpec getSecretKey(final String key) {
        //返回生成指定算法密钥生成器的 KeyGenerator 对象
        KeyGenerator kg = null;

        try {
            kg = KeyGenerator.getInstance(KEY_ALGORITHM);

            //AES 要求密钥长度为 128
            // //SecureRandom是生成安全随机数序列，password.getBytes()是种子，只要种子相同，序列就一样，所以生成的秘钥就一样。
            kg.init(128, new SecureRandom(key.getBytes()));

            //生成一个密钥
            SecretKey secretKey = kg.generateKey();
            // 转换为AES专用密钥
            return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);
        } catch (NoSuchAlgorithmException ex) {
            Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
        }

        return null;
    }

    public static void main(String[] args) throws UnsupportedEncodingException {

        String content = "hello,您好";
        String key = UUID.fastUUID().toString();
        System.out.println("key:" + key);
        System.out.println("content:" + content);
        String s1 = AESUtil.encrypt(content, key);
        System.out.println("密文:" + s1);
        System.out.println("原文:"+AESUtil.decrypt(s1, key));
    }

}